Ultrasonic transducers, employed for example for medical diagnostic purposes, are known in which the transducer is focused for an intended focal length. Such transducers generally include a spherically curved ceramic piezoelectric element supported on an acoustic backing material, or a flat piezoelectric element supported on a acoustic backing material with an acoustic lens disposed on the front surface of the flat element to provide the intended focusing. These known transducers are operative for only a single focal length, and a different transducer must be constructed for each focal length of interest.